diff -r 5f5e165c9a57 -r a25da86f7c8c progs/pprint/tree.sc
--- a/progs/pprint/tree.sc	Sat Apr 02 01:52:43 2022 +0100
+++ b/progs/pprint/tree.sc	Mon Aug 29 01:16:32 2022 +0200
@@ -1,9 +1,4 @@
-// scalatags 
-import ammonite.ops._
 
-import $ivy.`com.lihaoyi::scalatags:0.8.2` 
-import scalatags.Text.all._
-import scalatags.Text._
 
 // regular expressions including records
 abstract class Rexp 
@@ -62,6 +57,11 @@
 }
 
 
+// scalatags 
+import $ivy.`com.lihaoyi::scalatags:0.8.2` 
+import scalatags.Text.all._
+import scalatags.Text._
+
 def pp(r: Rexp) : TypedTag[String] = r match {
   case CHAR(c) => li(code(c.toString))
   case ALT(r1, r2) => li(code("+"), ul(pp(r1), pp(r2)))
@@ -104,6 +104,42 @@
 
 @main
 def main(fname: String) = {
-  val content = index(List(r1))
-  write.over(pwd / fname, content)
+  val content = index(List(r1, r2, evil2))
+  os.write.over(os.pwd / fname, content)
 }  
+
+
+  
+// scalatags 
+import $ivy.`com.lihaoyi::scalatags:0.8.2` 
+import scalatags.Text.all._
+import scalatags.Text._
+
+def pp(r: Rexp) : TypedTag[String] = r match {
+  case CHAR(c) => li(code(c.toString))
+  case ALTs(rs) => li(code("+"), ul(rs.map(pp)))
+  case SEQs(rs) => li(code(raw("&middot")), ul(rs.map(pp)))
+  case STAR(r1) => li(code("*"), ul(pp(r1)))
+  case ZERO => li(code("0"))
+  case ONE => li(code("1"))
+  //case SPECIAL(s) => li(code(raw(s)))
+} 
+
+def mktree(r: Rexp) = 
+   ul(cls := "tree")(pp(r))
+
+
+def index(rs: List[Rexp]) = 
+  html(
+    head(link(rel := "stylesheet", href := "./style.css")),
+    body(rs.map(mktree))
+  )
+
+
+@main
+def main(fname: String) = {
+  val r = ("a" | "ab" | "a") ~ ("c" | "bc")
+  val strs = List("","a","ab","abc")
+  val content = index(strs.map(s => ders(s.toList, r)))
+  os.write.over(os.pwd / fname, content)
+}